阅读说明：本技术 建筑垃圾海绵路面的浸水-循环交通荷载测试装置及方法 (Device and method for testing soaking-circulating traffic load of construction waste sponge pavement ) 是由 康宝 沈建海 包华 孙晓龙 章旬立 郑凌逶 徐亦采 谢新宇 胡庆红 于 2021-09-10 设计创作，主要内容包括：本发明公开了一种建筑垃圾海绵路面的浸水-循环交通荷载测试装置及方法,可用于开展建筑垃圾海绵路面在不同浸水程度下实施循环交通荷载的室内试验研究。测试装置具有荷载施加与监测功能,能够对建筑垃圾海绵路面模型施加不同形式的循环交通荷载,即时获取路面模型各层填料的温度变化、形变、渗流前后水头、渗流流量等数据。方法主要步骤包括：将建筑垃圾海绵路面填料分层填入测试装置内并埋设各种测量仪器,调节模型试验箱两侧活动挡板的高度用以控制路面模型浸水程度并通入稳定水流,通过一个与可调速电机相连的曲柄滑块机构为模型施加循环交通荷载,根据测试装置获取的各项数据计算得到各层填料在加荷过程中的渗透系数变化曲线与压缩曲线。(The invention discloses a device and a method for testing the soaking-circulating traffic load of a construction waste sponge pavement, which can be used for developing the indoor experimental research of the implementation of circulating traffic load of the construction waste sponge pavement under different soaking degrees. The testing device has the load applying and monitoring functions, can apply circulating traffic loads of different forms to the construction waste sponge pavement model, and can immediately acquire data such as temperature change, deformation, water heads before and after seepage, seepage flow and the like of fillers of each layer of the pavement model. The method mainly comprises the following steps: filling the construction waste sponge pavement filler into the testing device layer by layer and embedding various measuring instruments, adjusting the height of movable baffles at two sides of the model test box to control the water immersion degree of the pavement model and introduce stable water flow, applying circulating traffic load to the model through a crank-slider mechanism connected with a speed-adjustable motor, and calculating according to various data acquired by the testing device to obtain a permeability coefficient change curve and a compression curve of each layer of filler in the loading process.)

1. The soaking-circulating traffic load testing device for the construction waste sponge pavement is characterized by comprising a model test box, a circulating traffic load loading system and a monitoring system;

the model test box is provided with two side movable baffles with the height capable of being adjusted up and down, wherein a movable baffle port on one side is used as a water inlet, and a movable baffle port on the other side is used as a water outlet, and is used for adjusting the immersion degree of the pavement model; the bottom of the box body is provided with a seepage port, the box body is internally provided with a waterproof bottom layer formed by modifying and curing the slurry part of the construction waste, a small-particle-size block of the construction waste is filled to form a middle-layer filler, a large-particle-size block of the construction waste is filled to form an upper-layer filler, and the waterproof geotextiles are arranged among the fillers of different layers, on the inner wall of the box body and at the bottom of the box body; the upper surface of the upper-layer filler is provided with a concrete cushion plate, a test system guide rail is fixed on a central axis of the concrete cushion plate, the test system guide rail can allow a test system sliding block to freely reciprocate, and the test system sliding block is connected with a circulating traffic load loading system through a connecting rod;

the circulating traffic load loading system comprises a loading system sliding block, a speed-adjustable motor, a loading system guide rail, a balance block, a connecting rod, a crank and a rocker; the balance block is fixed at one end of the loading system guide rail, the speed-adjustable motor drives the crank to do circular motion with different periods around a fixed point, the crank drives the loading system slide block to do reciprocating motion with different periods on the loading system guide rail through the rocker, and then the loading system slide block drives the test system slide block on the model test box to do reciprocating motion with the same period on the test system guide rail through the connecting rod, so that the cyclic loading of traffic load on the road surface model is simulated;

the monitoring system comprises a flowmeter, a water head pipe, an optical fiber and a temperature sensor and is used for monitoring the temperature change, the deformation, the water heads before and after seepage and the seepage flow of the fillers at each layer of the pavement model under the cyclic traffic load; the flowmeter is embedded in the interface between the upper-layer filler and the middle-layer filler and the interface between the middle-layer filler and the waterproof bottom layer; the lower port of the water head pipe is embedded in the interface of the upper-layer filler and the middle-layer filler, the interface of the middle-layer filler and the waterproof bottom layer and the bottom surface of the waterproof bottom layer; the optical fibers are embedded in the top surface of the upper-layer filler, the interface of the upper-layer filler and the middle-layer filler, the interface of the middle-layer filler and the waterproof bottom layer and the bottom surface of the waterproof bottom layer; probes of the temperature sensor are embedded in four interfaces which are the same as the embedded positions of the optical fibers; the side wall of the box body is provided with a plurality of holes, the flowmeter, the water head pipe, the optical fiber and the temperature sensor are embedded and installed at a designed measuring point through the holes, and are led out of the box body to read monitoring data, and sealing treatment is carried out at the holes.

2. The device for testing the soaking-circulating traffic load of the construction waste sponge pavement as claimed in claim 1, wherein the movable baffles on two sides of the model test box are adjusted to be generally the same height, the opening of the movable baffle on one side is used as a water inlet, and the opening of the movable baffle on the other side slightly protrudes to be used as a water outlet.

3. The device for testing the soaking-circulating traffic load of the construction waste sponge pavement as claimed in claim 1, wherein the model test box is required to be synchronously embedded and installed with a flowmeter, an optical fiber and a temperature sensor in the filling process, and is used for monitoring the pavement model in real time in the subsequent loading process.

4. The device for testing the submergence-circulation traffic load of the construction waste sponge pavement as claimed in claim 1, wherein the loading system sliding block and the testing system sliding block are coplanar.

5. The apparatus of claim 1, wherein the flow meter is a Pitotbar flow meter, and comprises a measuring rod, a differential pressure transmitter and a flow display instrument, the measuring rod is embedded in an interface between the upper layer filler and the middle layer filler, and an interface between the middle layer filler and the impermeable bottom layer, and the flow display instrument is led out of the model test box to facilitate real-time data reading.

6. The device for testing the soaking-circulating traffic load of the construction waste sponge pavement according to claim 1, wherein for the flowmeters, 2 flowmeters are symmetrically embedded in each interface by the center of the plane midpoint, and the total number of the flowmeters is 4;

2 water head pipes are embedded in each interface, 6 water head pipes are totally arranged, and the vertical sections of the water head pipes are led out of the model test box, so that the water head change of each water head pipe can be conveniently monitored in real time;

for the optical fibers, 3 optical fibers are uniformly distributed on each interface, 12 optical fibers are counted, and the thickness change of each layer of filler at different positions can be calculated according to the initial quantity of each optical fiber at different positions and the deformation quantity in the test process;

for the temperature sensors, 2 temperature sensors are embedded in each interface, and 8 temperature sensors are used for monitoring the temperature change of each layer of filler in the test process in real time.

7. The apparatus for testing flooding-circulating traffic load of construction waste sponge pavement according to claim 1, wherein the seepage flow at the interface of the upper layer filler and the middle layer filler and at the interface of the middle layer filler and the water-impermeable bottom layer is measured by a flow meter, and the seepage flow of the water-impermeable bottom layer is measured after the water seeped from the seepage port is collected by the fluid collecting device and the mass of the water-impermeable bottom layer is measured and converted into the seepage flow.

8. The soaking-circulating traffic load testing device for the construction waste sponge pavement, according to claim 1, is characterized in that the height difference delta H of the water head of the seepage water flow of the upper and lower interfaces of each layer of packing is obtained according to the height of the water column of the water head pipe, the thickness H of each layer of packing is obtained according to optical fiber monitoring data, the seepage flow Q of each layer of packing is obtained by a flowmeter, the area of the cross section of each layer of packing is recorded as A, and the viscosity mu of water at the current temperature is obtained by looking up a table according to the temperature measured by a temperature sensor; and (3) calculating the permeability coefficient k of each layer of the filler according to the following formula:

9. the device for testing the soaking-circulating traffic load of the construction waste sponge pavement as claimed in claim 1, wherein a curve of the thickness of each layer of the filler along with the change of the loading time, namely a compression curve, is obtained by calculation according to the embedded optical fiber monitoring data.

10. A method of implementing the test device of any one of claims 1-9, comprising the steps of:

(1) preparation of a testing device and a model material: after the field is leveled, the testing device is placed at a proper position of the field, and all layers of fillers on the construction waste sponge pavement are transported to the vicinity of the field;

(2) the packing and monitoring system is arranged: firstly, laying and installing permeable geotextile, optical fibers, temperature sensors and water head pipes at the bottom of a model test box, then slowly and densely filling impermeable bottom filler of a sponge pavement, then laying permeable geotextile and embedding and installing flow meters, optical fibers, temperature sensors and water head pipes; continuously and slowly and densely filling the middle layer filler, then laying permeable geotextile, and embedding and installing a flowmeter, an optical fiber, a temperature sensor and a water head pipe; continuously and slowly and densely filling the upper-layer filler, laying permeable geotextile, embedding and installing optical fibers and a temperature sensor, completing filling of the filler and installation of a monitoring system, and finally covering a concrete cushion plate on the top surface;

(3) installing and connecting a cyclic traffic load loading system: installing a test system guide rail on a central axis of the concrete cushion plate, placing a test system sliding block on the test system guide rail, adjusting the quality of the test system sliding block according to the required traffic load, and connecting the test system sliding block with a loading system sliding block in a cyclic traffic load loading system through a connecting rod;

(4) setting the water immersion degree of a permeable layer: after the water immersion degree of a permeable formation of a road model to be tested is determined, moving the movable baffles on the two sides up and down to a set position, connecting a water pipe at the openings of the movable baffles, injecting water into the opening of the movable baffle on one side, and collecting effluent water at the opening of the movable baffle on the other side and a seepage opening at the bottom of a model test box;

(5) checking the working state of the monitoring system: checking whether optical fiber monitoring data, the water column height of a water head pipe, the reading of a flowmeter and the reading of a temperature sensor can be normally acquired after water is injected for half an hour to one hour, and if the optical fiber monitoring data, the water column height of the water head pipe, the reading of the flowmeter and the reading of the temperature sensor cannot be normally acquired, dismantling each component, cleaning the filler and executing the step (2) again;

(6) load application: setting the mass of a loading system slide block, the mass of a balance block and the rotating speed of a speed-adjustable motor in a cyclic traffic load loading system, then starting the speed-adjustable motor to apply cyclic load, and keeping the detection of a monitoring system and the motion state of each slide block in the loading process to ensure the normal acquisition of each test data;

(7) data acquisition and processing: and (3) according to the water column height of a water head pipe in the model test box, the height of a movable baffle opening, the reading of a flowmeter, the monitoring data of optical fibers and the reading of a temperature sensor, arranging and calculating to obtain a permeability coefficient change curve and a compression curve of each layer of filler in the loading process.

Technical Field

The invention belongs to the field of roadbed construction, and particularly relates to a device and a method for testing soaking-circulating traffic load of a construction waste sponge pavement.

Background

Along with the continuous increase of urbanization scale in China, the construction industry develops rapidly, and the amount of construction waste generated along with the rapid increase of the urbanization scale becomes a great problem which needs to be faced and solved in the economic development process of various cities. At present, the recycling mode of the construction waste in China mainly comprises the steps of building the landscape with the construction waste, producing recycled aggregate, producing environment-friendly bricks, filling road beds and the like. In recent years, the scale of the traffic engineering construction of China is gradually increased, so that the demand of sandstone materials is continuously increased. Under the concept of sustainable development, the research and application of the construction waste in the aspect of road subgrade filling show great significance. The recycling of the construction waste has a series of effects of avoiding the construction waste from occupying land resources, thereby improving the utilization efficiency of urban land resources, improving the scientificity and normalization of resource development of the construction waste, relieving the situation of shortage of sandstone materials, avoiding the problem of environmental pollution caused by improper treatment of the construction waste, and the like.

After the construction waste is intensively recycled, the construction waste is usually primarily selected, then the residue soil is removed by adopting a vibrating feeder, then the construction waste is crushed into blocks with different sizes by using a jaw crusher, and finally the construction waste is screened by adopting a screen frame vibrating electric screen and a steel wire woven screen. The large-particle-size block can be used as an upper-layer filler of the pavement, the small-particle-size block can be used as a middle-layer filler of the pavement, and the slurry part in the construction waste can be used as a waterproof bottom layer of the pavement after being modified and cured.

In order to further promote the application of the construction waste in the roadbed engineering, research on the use of the construction waste as a road surface filler is necessary. The tunnel pavement is subjected to the circulation action of traffic load, the safety and durability of the tunnel pavement are directly influenced by the permeability and the deformability of the tunnel pavement, and a research method capable of dynamically testing the permeability and the deformability of the construction waste sponge pavement under the traffic circulation load is not available at present. Based on the above, the development of the cyclic loading indoor test on the construction waste sponge pavement is a direct, effective and credible means for researching the dynamic characteristics of the construction waste sponge pavement.

Disclosure of Invention

The construction waste sponge pavement structure can be generally divided into three layers according to the permeability, and the permeability of the roadbed filling materials from top to bottom is gradually weakened. The invention provides a device and a method for testing the soaking-circulating traffic load of a construction waste sponge pavement, aiming at obtaining the change characteristics of roadbed performances such as permeability, deformability and the like of fillers of each layer under the condition of the soaking-circulating traffic load of the construction waste sponge pavement.

The purpose of the invention is realized by the following technical scheme:

the invention provides a soaking-circulating traffic load testing device for a construction waste sponge pavement, which comprises a model test box, a circulating traffic load loading system and a monitoring system, wherein the model test box comprises a water tank, a circulating and water tank;

the model test box is provided with two side movable baffles with the height capable of being adjusted up and down, wherein a movable baffle port on one side is used as a water inlet, and a movable baffle port on the other side is used as a water outlet, and is used for adjusting the immersion degree of the pavement model; the bottom of the box body is provided with a seepage port, the box body is internally provided with a waterproof bottom layer formed by modifying and curing the slurry part of the construction waste, a small-particle-size block of the construction waste is filled to form a middle-layer filler, a large-particle-size block of the construction waste is filled to form an upper-layer filler, and the waterproof geotextiles are arranged among the fillers of different layers, on the inner wall of the box body and at the bottom of the box body; the upper surface of the upper-layer filler is provided with a concrete cushion plate, a test system guide rail is fixed on a central axis of the concrete cushion plate, the test system guide rail can allow a test system sliding block to freely reciprocate, and the test system sliding block is connected with a circulating traffic load loading system through a connecting rod;

the circulating traffic load loading system comprises a loading system sliding block, a speed-adjustable motor, a loading system guide rail, a balance block, a connecting rod, a crank and a rocker; the balance block is fixed at one end of the loading system guide rail, the speed-adjustable motor drives the crank to do circular motion with different periods around a fixed point, the crank drives the loading system slide block to do reciprocating motion with different periods on the loading system guide rail through the rocker, and then the loading system slide block drives the test system slide block on the model test box to do reciprocating motion with the same period on the test system guide rail through the connecting rod, so that the cyclic loading of traffic load on the road surface model is simulated;

the monitoring system comprises a flowmeter, a water head pipe, an optical fiber and a temperature sensor and is used for monitoring the temperature change, the deformation, the water heads before and after seepage and the seepage flow of the fillers at each layer of the pavement model under the cyclic traffic load; the flowmeter is embedded in the interface between the upper-layer filler and the middle-layer filler and the interface between the middle-layer filler and the waterproof bottom layer; the lower port of the water head pipe is embedded in the interface of the upper-layer filler and the middle-layer filler, the interface of the middle-layer filler and the waterproof bottom layer and the bottom surface of the waterproof bottom layer; the optical fibers are embedded in the top surface of the upper-layer filler, the interface of the upper-layer filler and the middle-layer filler, the interface of the middle-layer filler and the waterproof bottom layer and the bottom surface of the waterproof bottom layer; probes of the temperature sensor are embedded in four interfaces which are the same as the embedded positions of the optical fibers; the side wall of the box body is provided with a plurality of holes, the flowmeter, the water head pipe, the optical fiber and the temperature sensor are embedded and installed at a designed measuring point through the holes, and are led out of the box body to read monitoring data, and sealing treatment is carried out at the holes.

Further, the movable baffles on the two sides of the model test box are usually adjusted to the same height, the opening of the movable baffle on one side is used as a water inlet, and the opening of the movable baffle on the other side slightly protrudes to be used as a water outlet.

Furthermore, the model test box needs to be synchronously embedded and installed with a flowmeter, an optical fiber and a temperature sensor in the filling process, and is used for monitoring the pavement model in real time in the subsequent loading process.

Further, the loading system slide block and the testing system slide block are coplanar.

Furthermore, the flow meter adopts a Pitotbar flow meter and consists of a detection rod, a differential pressure transmitter and a flow display instrument, wherein the detection rod is embedded in an interface between the upper layer filler and the middle layer filler and an interface between the middle layer filler and the impermeable bottom layer, and the flow display instrument is led out of the model test box, so that data can be conveniently read in real time.

Further, for the flowmeters, each interface is symmetrically embedded with 2 flowmeters by the center of the plane midpoint, and the total number of the flowmeters is 4;

2 water head pipes are embedded in each interface, 6 water head pipes are totally arranged, and the vertical sections of the water head pipes are led out of the model test box, so that the water head change of each water head pipe can be conveniently monitored in real time;

for the optical fibers, 3 optical fibers are uniformly distributed on each interface, 12 optical fibers are counted, and the thickness change of each layer of filler at different positions can be calculated according to the initial quantity of each optical fiber at different positions and the deformation quantity in the test process;

for the temperature sensors, 2 temperature sensors are embedded in each interface, and 8 temperature sensors are used for monitoring the temperature change of each layer of filler in the test process in real time.

Furthermore, the seepage flow of the interface of the upper layer filler and the middle layer filler and the interface of the middle layer filler and the impervious bottom layer is measured by a flowmeter, and the seepage flow of the impervious bottom layer is measured after the fluid collecting device collects the water seeped from the seepage port, and the mass of the seepage flow is converted into the seepage flow.

Further, the height of the water column of the water head pipe is used for obtaining the seepage water head of the upper and lower interfaces of each layer of fillingThe height difference delta H is obtained by monitoring data through optical fibers to obtain the thickness H of each layer of filler, the seepage flow Q of each layer of filler is obtained by a flowmeter, the water cross section area of each layer of filler is recorded as A, and the viscosity mu of water at the current temperature is obtained by looking up a table according to the temperature measured by a temperature sensor; and (3) calculating the permeability coefficient k of each layer of the filler according to the following formula:

furthermore, a curve of the thickness of each layer of the filler along with the change of the loading time, namely a compression curve, is obtained by calculation according to the monitoring data of the embedded optical fiber.

The invention also provides an implementation method of the construction waste sponge pavement soaking-circulating traffic load testing device, which comprises the following steps:

(1) preparation of a testing device and a model material: after the field is leveled, the testing device is placed at a proper position of the field, and all layers of fillers on the construction waste sponge pavement are transported to the vicinity of the field;

(2) the packing and monitoring system is arranged: firstly, laying and installing permeable geotextile, optical fibers, temperature sensors and water head pipes at the bottom of a model test box, then slowly and densely filling impermeable bottom filler of a sponge pavement, then laying permeable geotextile and embedding and installing flow meters, optical fibers, temperature sensors and water head pipes; continuously and slowly and densely filling the middle layer filler, then laying permeable geotextile, and embedding and installing a flowmeter, an optical fiber, a temperature sensor and a water head pipe; continuously and slowly and densely filling the upper-layer filler, laying permeable geotextile, embedding and installing optical fibers and a temperature sensor, completing filling of the filler and installation of a monitoring system, and finally covering a concrete cushion plate on the top surface;

(3) installing and connecting a cyclic traffic load loading system: installing a test system guide rail on a central axis of the concrete cushion plate, placing a test system sliding block on the test system guide rail, adjusting the quality of the test system sliding block according to the required traffic load, and connecting the test system sliding block with a loading system sliding block in a cyclic traffic load loading system through a connecting rod;

(4) setting the water immersion degree of a permeable layer: after the water immersion degree of a permeable formation of a road model to be tested is determined, moving the movable baffles on the two sides up and down to a set position, connecting a water pipe at the openings of the movable baffles, injecting water into the opening of the movable baffle on one side, and collecting effluent water at the opening of the movable baffle on the other side and a seepage opening at the bottom of a model test box;

(5) checking the working state of the monitoring system: checking whether optical fiber monitoring data, the water column height of a water head pipe, the reading of a flowmeter and the reading of a temperature sensor can be normally acquired after water is injected for half an hour to one hour, and if the optical fiber monitoring data, the water column height of the water head pipe, the reading of the flowmeter and the reading of the temperature sensor cannot be normally acquired, dismantling each component, cleaning the filler and executing the step (2) again;

(6) load application: setting the mass of a loading system slide block, the mass of a balance block and the rotating speed of a speed-adjustable motor in a cyclic traffic load loading system, then starting the speed-adjustable motor to apply cyclic load, and keeping the detection of a monitoring system and the motion state of each slide block in the loading process to ensure the normal acquisition of each test data;

(7) data acquisition and processing: and (3) according to the water column height of a water head pipe in the model test box, the height of a movable baffle opening, the reading of a flowmeter, the monitoring data of optical fibers and the reading of a temperature sensor, arranging and calculating to obtain a permeability coefficient change curve and a compression curve of each layer of filler in the loading process.

The invention has the beneficial effects that: the invention can be used for developing indoor experimental research of circulating traffic load of construction waste sponge pavements under different water immersion degrees. The testing device has the load applying and monitoring functions, can apply circulating traffic loads of different forms to the construction waste sponge pavement model, and can immediately acquire data such as temperature change, deformation, water heads before and after seepage, seepage flow and the like of fillers of each layer of the pavement model. The model test and the testing device are used for analyzing the action mechanism of the circulating traffic load on the permeability and deformation characteristics of the construction waste sponge pavement under different water immersion degrees, and can be used for further developing pavement material and structure optimization research, so that the application and industrialization of the construction waste in the sponge pavement are promoted.

Drawings

FIG. 1 is a cross-sectional view of a model test chamber provided by an embodiment of the present invention;

FIG. 2 is a left side view of a model test chamber provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of a cyclical traffic load application provided by an embodiment of the present invention;

FIG. 4 is a schematic diagram of a cyclic traffic load loading system provided by an embodiment of the present invention;

in the figure, an upper layer of filler 1, a middle layer of filler 2, a waterproof bottom layer 3, a concrete cushion plate 4, a movable baffle 5, a water head pipe 6, a permeable geotextile 7, a temperature sensor 8, an optical fiber 9, a flowmeter 10, a seepage port 11, a test system guide rail 12, a test system sliding block 13, a connecting rod 14, a balance block 15, a rocker 16, a crank 17, a speed-adjustable motor 18, a loading system sliding block 19 and a loading system guide rail 20.

Detailed Description

For better understanding of the technical solutions of the present application, the following detailed descriptions of the embodiments of the present application are provided with reference to the accompanying drawings.

It should be understood that the embodiments described are only a few embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the examples of this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The construction waste sponge pavement structure for simulation of the testing device is divided into three layers, wherein an upper layer filler 1 is a large-particle-size block of construction waste, a middle layer filler 2 is a small-particle-size block of construction waste, and a waterproof bottom layer 3 is formed by modifying and curing a slurry part of the construction waste.

The embodiment of the invention provides a construction waste sponge pavement soaking-circulating traffic load testing device which mainly comprises a model test box, a circulating traffic load loading system and a monitoring system.

1. Model test box

As shown in fig. 1 and 2, the model test box is provided with two side movable baffles 5 with height adjustable up and down, the two side movable baffles 5 are generally adjusted to the same height, the opening of one side movable baffle is used as a water inlet, the opening of the other side movable baffle is slightly protruded to be used as a water outlet, and the two side movable baffles are used for adjusting and controlling the water immersion degree of the road surface model, for example, the water immersion degree of a road surface permeable layer is set to be 0%, 50%, 100% or 150%; the bottom of the box body is provided with a seepage port 11, the box body is internally provided with an impermeable bottom layer 3 formed by modifying and curing a building garbage slurry part, a small-particle-size block of the building garbage is filled into a middle-layer filler 2, a large-particle-size block of the building garbage is filled into an upper-layer filler 1, and permeable geotextiles 7 are arranged among different layers of fillers, on the inner wall of the box body and at the bottom of the box body to play roles of separation, permeability and filtration; in the filling process, the flowmeter 10, the temperature sensor 8, the optical fiber 9 and the like need to be embedded and installed synchronously, and the method is used for monitoring the model in real time in the subsequent loading process; a plurality of holes are formed in each side wall of the box body, and measuring instruments such as a flowmeter 10, a temperature sensor 8, an optical fiber 9 and a water head pipe 6 are embedded and installed at designed measuring points through the holes and are led out of the box body to read monitoring data; sealing the hole to prevent water in the test box from seeping out of the hole; the upper surface of the upper-layer filler 1 is provided with a concrete cushion plate 4, a test system guide rail 12 is fixed on a central axis of the concrete cushion plate 4 and can be used for a test system slider 13 to freely reciprocate, the test system slider 13 is connected with a circulating traffic load loading system through a connecting rod 14, as shown in fig. 3, a loading system slider 19 in the circulating traffic load loading system drives the test system slider 13 to reciprocate in the same period through the connecting rod 14, and therefore the application of the circulating traffic load on the construction waste sponge pavement model is achieved. Wherein the loading system slide 19 and the testing system slide 13 are coplanar.

2. Cyclic traffic load loading system

As shown in fig. 4, the cyclic traffic load loading system mainly comprises a loading system slider 19, a speed-adjustable motor 18, a loading system guide rail 20, a balance weight 15, a connecting rod 14, a crank 17, a rocker 16 and the like. The counterbalance 15 is fixed to one end of the loading system rail 20 for preventing the loading system slider 19 from causing the loading system to roll over during sliding. The adjustable speed motor 18 drives the crank 17 to do circular motion with different periods around a fixed point, the crank 17 drives the loading system slide block 19 to do reciprocating motion with different periods on the loading system guide rail 20 through the rocker 16, and then the loading system slide block 19 drives the test system slide block 13 on the test box to do reciprocating motion with the same period on the test system guide rail 12 through the connecting rod 14, so that the cyclic loading of traffic load on a road model is simulated.

3. Monitoring system

The monitoring system mainly monitors the temperature change, deformation, water heads before and after seepage, seepage flow and other data of the fillers of each layer of the pavement model under the cyclic traffic load.

Wherein the flow is measured using a Pitotbar flow meter. The Pitotbar flowmeter is a type of bypass differential pressure flowmeter developed based on the pitot tube speed measurement principle. The Pitoba flowmeter consists of a detection rod, a differential pressure transmitter and a flow display instrument. Compared with other flowmeters, the Pitotbar flowmeter has the advantages of simple structure, light weight, low manufacturing cost, convenience in mounting and dismounting, convenience in maintenance and replacement, low pressure loss and energy consumption, wide applicable fluid type and working state range and the like. The seepage flow of the junction of the upper layer and the middle layer and the seepage flow of the junction of the middle layer and the lower layer are measured by a Pitotbar flowmeter, the mass of the seepage flow of the bottom layer is measured after the seepage flow is collected by a fluid collecting device and seeped out from the seepage port 11, the mass of the seepage flow is converted into the seepage flow, and each seepage flow is used for calculating the permeability coefficient of each layer.

The detection rod of the Pitotbar flowmeter is embedded in the interface between the upper layer filler 1 and the middle layer filler 2, and the interface between the middle layer filler 2 and the impervious bottom layer 3, 2 flowmeters 10 are symmetrically embedded in the two interfaces by using the center of the plane, the total number of the flowmeters 10 is 4, and the display instrument of each flowmeter 10 can be led out of the model test box to conveniently read data in real time.

The lower ports of the water head pipes 6 are embedded at the interface of the upper-layer filler 1 and the middle-layer filler 2, the interface of the middle-layer filler 2 and the waterproof bottom layer 3 and the bottom surface of the waterproof bottom layer 3, 2 water head pipes 6 are embedded at each interface, 6 water head pipes 6 are counted, and the vertical sections of the water head pipes 6 are led out of the model test box, so that the water head change of each water head pipe 6 can be conveniently monitored in real time.

The optical fibers 9 are buried in the top surface of the upper-layer filler 1, the interface of the upper-layer filler 1 and the middle-layer filler 2, the interface of the middle-layer filler 2 and the waterproof bottom layer 3 and the bottom surface of the waterproof bottom layer 3, 3 optical fibers 9 are uniformly distributed on each interface, the total number of the optical fibers 9 is 12, and the thickness change of each layer of filler at different positions can be calculated according to the initial quantity of each optical fiber at different positions and the deformation quantity in the test process.

The probes of the temperature sensors 8 are embedded in four interfaces at the same position as the optical fiber 9, each interface is embedded with 2 temperature sensors 8, and the total number of the temperature sensors 8 is 8, so that the temperature change of each layer of filler in the test process can be monitored in real time.

Acquiring the height difference delta H of the water head of the seepage water flow of the upper interface and the lower interface of each layer of the packing by the water head pipe 6, acquiring the thickness H of each layer of the packing by monitoring data through an optical fiber 9, acquiring the seepage flow Q of each layer of the packing by a flowmeter 10, recording the water cross section area of each layer of the packing as A, and acquiring the viscosity mu of the water at the current temperature by looking up a table according to the temperature measured by a temperature sensor 8; and (3) calculating the permeability coefficient k of each layer of the filler according to the following formula:

and calculating an h-t curve, namely a compression curve, of the thickness of each layer of the filler along with the change of the loading time according to the monitoring data of the embedded optical fiber 9.

The concrete steps of the device for testing the soaking-circulating traffic load of the construction waste sponge pavement provided by the embodiment are as follows:

(1) test apparatus and model material preparation

After the field is leveled, the testing device is placed at a proper position of the field, and all layers of fillers on the construction waste sponge pavement are transported to the vicinity of the field;

(2) packing and monitoring system arrangement

Firstly, paving and installing permeable geotextile 7, optical fiber 9, temperature sensor 8 and water head pipe 6 at the bottom of a model test box, then slowly and densely filling the impermeable bottom layer 3 filler of the sponge pavement, paving the permeable geotextile 7 and embedding and installing flowmeter 10, optical fiber 9, temperature sensor 8 and water head pipe 6; the middle layer filler 2 is continuously and slowly and densely filled, then the permeable geotextile 7 is laid, and the flowmeter 10, the optical fiber 9, the temperature sensor 8 and the water head pipe 6 are embedded and installed; continuously and slowly and densely filling the upper-layer filler 1, laying a permeable geotextile 7, embedding and installing an optical fiber 9 and a temperature sensor 8, completing filling of the filler and installation of a monitoring system, and finally covering a concrete cushion plate 4 on the top surface;

(3) installation and connection circulating traffic load loading system

Installing a test system guide rail 12 on the axis of a concrete cushion plate 4 of the model test box, then placing a test system sliding block 13 on the test system guide rail 12, adjusting the mass of the test system sliding block 13 according to the required traffic load, and connecting the test system sliding block 13 with a loading system sliding block 19 in a circulating traffic load loading system placed beside the model test box through a connecting rod 14;

(4) set the degree of water immersion of the permeable layer

After determining the water immersion degree of a permeable formation of the pavement model to be tested, moving the movable baffles 5 on the left side and the right side up and down to set positions, connecting water pipes at the openings of the movable baffles on the two sides, injecting water into the opening of the movable baffle on the right side, and collecting effluent at the opening of the movable baffle on the left side and the seepage opening 11 at the bottom of the model test box;

(5) checking and monitoring system working state

Checking whether the monitoring data of the optical fiber 9, the water column height of the water head pipe 6, the reading of the flowmeter 10 and the reading of the temperature sensor 8 can be normally acquired after water is injected for half an hour to one hour, and if the normal acquisition cannot be realized, dismantling all the parts, cleaning the filler and executing the step (2) again;

(6) application of load

Setting the mass of a loading system slider 19, the mass of a balance block 15 and the rotating speed of a speed-adjustable motor 18 in a cyclic traffic load loading system, then starting the speed-adjustable motor 18 to apply cyclic load, and keeping checking on a monitoring system and the motion state of each slider in the loading process to ensure the normal acquisition of each test data;

(7) data acquisition and processing

And (3) obtaining a permeability coefficient change curve and a compression curve of each layer of filler in the loading process according to the arrangement calculation of the height of the water column 6 of the water head pipe in the model test box, the height of the movable baffle opening, the reading of the flowmeter 10, the monitoring data of the optical fiber 9, the reading of the temperature sensor 8 and the like.

The above description is only for the purpose of illustrating the preferred embodiments of the one or more embodiments of the present disclosure, and is not intended to limit the scope of the one or more embodiments of the present disclosure, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the one or more embodiments of the present disclosure should be included in the scope of the one or more embodiments of the present disclosure.